Abstract. In this paper, an enhanced beam model based on a 5-parameter displacement field, recently proposed by the authors and able to reproduce the Poisson effect in transverse direction is presented, and utilized to simulate the fully geometrically nonlinear response of elastic beam structures. The adoption of the linear solution as approximation functions for the nonlinear case allows prediction of nonlinear response of problems involving complex geometries with a relatively small computational effort. Several numerical examples of benchmark problems are analyzed, highlighting the characteristic features of the proposed five-parameter model and comparing the results with those obtained using the classical Bernoulli beam model and 3D finite element model.